/*
* @(#)StringCoding.java 1.20 06/10/06
*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.lang;
import java.io.CharConversionException;
import java.io.UnsupportedEncodingException;
import java.lang.ref.SoftReference;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.BufferOverflowException;
import java.nio.BufferUnderflowException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.CoderResult;
import java.nio.charset.CodingErrorAction;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.MalformedInputException;
import java.nio.charset.UnsupportedCharsetException;
import java.util.Arrays;
import sun.misc.MessageUtils;
import sun.nio.cs.HistoricallyNamedCharset;
/**
* Utility class for string encoding and decoding.
*/
class StringCoding {
private StringCoding() { }
/* The cached coders for each thread
*/
private static ThreadLocal decoder = new ThreadLocal();
private static ThreadLocal encoder = new ThreadLocal();
private static boolean warnUnsupportedCharset = true;
private static Object deref(ThreadLocal tl) {
SoftReference sr = (SoftReference)tl.get();
if (sr == null)
return null;
return sr.get();
}
private static void set(ThreadLocal tl, Object ob) {
tl.set(new SoftReference(ob));
}
// Trim the given byte array to the given length
//
private static byte[] safeTrim(byte[] ba, int len, Charset cs) {
if (len == ba.length
&& (System.getSecurityManager() == null
|| cs.getClass().getClassLoader0() == null))
return ba;
else
return Arrays.copyOf(ba, len);
}
// Trim the given char array to the given length
//
private static char[] safeTrim(char[] ca, int len, Charset cs) {
if (len == ca.length
&& (System.getSecurityManager() == null
|| cs.getClass().getClassLoader0() == null))
return ca;
else
return Arrays.copyOf(ca, len);
}
private static int scale(int len, float expansionFactor) {
// We need to perform double, not float, arithmetic; otherwise
// we lose low order bits when len is larger than 2**24.
return (int)(len * (double)expansionFactor);
}
private static Charset lookupCharset(String csn) {
if (Charset.isSupported(csn)) {
try {
return Charset.forName(csn);
} catch (UnsupportedCharsetException x) {
throw new Error(x);
}
}
return null;
}
private static void warnUnsupportedCharset(String csn) {
if (warnUnsupportedCharset) {
// Use sun.misc.MessageUtils rather than the Logging API or
// System.err since this method may be called during VM
// initialization before either is available.
MessageUtils.err("WARNING: Default charset " + csn +
" not supported, using ISO-8859-1 instead");
warnUnsupportedCharset = false;
}
}
// -- Decoding --
private static class StringDecoder {
private final String requestedCharsetName;
private final Charset cs;
private final CharsetDecoder cd;
private StringDecoder(Charset cs, String rcn) {
this.requestedCharsetName = rcn;
this.cs = cs;
this.cd = cs.newDecoder()
.onMalformedInput(CodingErrorAction.REPLACE)
.onUnmappableCharacter(CodingErrorAction.REPLACE);
}
String charsetName() {
if (cs instanceof HistoricallyNamedCharset)
return ((HistoricallyNamedCharset)cs).historicalName();
return cs.name();
}
final String requestedCharsetName() {
return requestedCharsetName;
}
char[] decode(byte[] ba, int off, int len) {
int en = scale(len, cd.maxCharsPerByte());
char[] ca = new char[en];
if (len == 0)
return ca;
cd.reset();
ByteBuffer bb = ByteBuffer.wrap(ba, off, len);
CharBuffer cb = CharBuffer.wrap(ca);
try {
CoderResult cr = cd.decode(bb, cb, true);
if (!cr.isUnderflow())
cr.throwException();
cr = cd.flush(cb);
if (!cr.isUnderflow())
cr.throwException();
} catch (CharacterCodingException x) {
// Substitution is always enabled,
// so this shouldn't happen
throw new Error(x);
}
return safeTrim(ca, cb.position(), cs);
}
}
static char[] decode(String charsetName, byte[] ba, int off, int len)
throws UnsupportedEncodingException
{
StringDecoder sd = (StringDecoder)deref(decoder);
String csn = (charsetName == null) ? "ISO-8859-1" : charsetName;
if ((sd == null) || !(csn.equals(sd.requestedCharsetName())
|| csn.equals(sd.charsetName()))) {
sd = null;
try {
Charset cs = lookupCharset(csn);
if (cs != null)
sd = new StringDecoder(cs, csn);
} catch (IllegalCharsetNameException x) {}
if (sd == null)
throw new UnsupportedEncodingException(csn);
set(decoder, sd);
}
return sd.decode(ba, off, len);
}
static char[] decode(Charset cs, byte[] ba, int off, int len) {
StringDecoder sd = new StringDecoder(cs, cs.name());
byte[] b = Arrays.copyOf(ba, ba.length);
return sd.decode(b, off, len);
}
static char[] decode(byte[] ba, int off, int len) {
String csn = Charset.defaultCharset().name();
try {
return decode(csn, ba, off, len);
} catch (UnsupportedEncodingException x) {
warnUnsupportedCharset(csn);
}
try {
return decode("ISO-8859-1", ba, off, len);
} catch (UnsupportedEncodingException x) {
// If this code is hit during VM initialization, MessageUtils is
// the only way we will be able to get any kind of error message.
MessageUtils.err("ISO-8859-1 charset not available: "
+ x.toString());
// If we can not find ISO-8859-1 (a required encoding) then things
// are seriously wrong with the installation.
System.exit(1);
return null;
}
}
// -- Encoding --
private static class StringEncoder {
private Charset cs;
private CharsetEncoder ce;
private final String requestedCharsetName;
private StringEncoder(Charset cs, String rcn) {
this.requestedCharsetName = rcn;
this.cs = cs;
this.ce = cs.newEncoder()
.onMalformedInput(CodingErrorAction.REPLACE)
.onUnmappableCharacter(CodingErrorAction.REPLACE);
}
String charsetName() {
if (cs instanceof HistoricallyNamedCharset)
return ((HistoricallyNamedCharset)cs).historicalName();
return cs.name();
}
final String requestedCharsetName() {
return requestedCharsetName;
}
byte[] encode(char[] ca, int off, int len) {
int en = scale(len, ce.maxBytesPerChar());
byte[] ba = new byte[en];
if (len == 0)
return ba;
ce.reset();
ByteBuffer bb = ByteBuffer.wrap(ba);
CharBuffer cb = CharBuffer.wrap(ca, off, len);
try {
CoderResult cr = ce.encode(cb, bb, true);
if (!cr.isUnderflow())
cr.throwException();
cr = ce.flush(bb);
if (!cr.isUnderflow())
cr.throwException();
} catch (CharacterCodingException x) {
// Substitution is always enabled,
// so this shouldn't happen
throw new Error(x);
}
return safeTrim(ba, bb.position(), cs);
}
}
static byte[] encode(String charsetName, char[] ca, int off, int len)
throws UnsupportedEncodingException
{
StringEncoder se = (StringEncoder)deref(encoder);
String csn = (charsetName == null) ? "ISO-8859-1" : charsetName;
if ((se == null) || !(csn.equals(se.requestedCharsetName())
|| csn.equals(se.charsetName()))) {
se = null;
try {
Charset cs = lookupCharset(csn);
if (cs != null)
se = new StringEncoder(cs, csn);
} catch (IllegalCharsetNameException x) {}
if (se == null)
throw new UnsupportedEncodingException (csn);
set(encoder, se);
}
return se.encode(ca, off, len);
}
static byte[] encode(Charset cs, char[] ca, int off, int len) {
StringEncoder se = new StringEncoder(cs, cs.name());
char[] c = Arrays.copyOf(ca, ca.length);
return se.encode(c, off, len);
}
static byte[] encode(char[] ca, int off, int len) {
String csn = Charset.defaultCharset().name();
try {
return encode(csn, ca, off, len);
} catch (UnsupportedEncodingException x) {
warnUnsupportedCharset(csn);
}
try {
return encode("ISO-8859-1", ca, off, len);
} catch (UnsupportedEncodingException x) {
// If this code is hit during VM initialization, MessageUtils is
// the only way we will be able to get any kind of error message.
MessageUtils.err("ISO-8859-1 charset not available: "
+ x.toString());
// If we can not find ISO-8859-1 (a required encoding) then things
// are seriously wrong with the installation.
System.exit(1);
return null;
}
}
}
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